Best oil for high mileage
“I’ve driven my 1999 Chevy van more than 1 million miles. I installed AMSOIL synthetic 0W-30 motor oil in the engine at 68,250 miles and at 68,745 miles installed AMSOIL lubes throughout the drive train. The original 350 gasoline engine was replaced in the fall of 2007... at 930,599 miles after a valve keeper in the engine wore out. It still has the original transmission with more than 1,000,000 miles and it has never been overhauled.”
– AMSOIL Dealer John Schlimmer, Greenville, Ohio

AMSOIL Dealer John Schlimmer of Greenville, Ohio drives a 1999 Chevy G-3500 Express delivery van over the road between 110,000 to 120,000 miles a year. When Schlimmer learned about AMSOIL synthetic motor oils and lubricants in 2000, he installed AMSOIL products throughout the vehicle’s drive train.

He first installed AMSOIL 0W-30 Synthetic Motor Oil and went from changing his oil every two weeks to once every three months. He also installed an AMSOIL oil filter, AMSOIL Multi-Purpose Synthetic Grease, Automatic Transmission Fluid, and AMSOIL 75W-90 Synthetic Gear Oil in the vehicle’s differential. Schlimmer drove the van until October 2007, when a valve keeper broke on the 5.7 liter, 350 gasoline engine. Schlimmer said the actual mileage on the engine did not factor in more than 6,000 hours of idle time. It had 930,599 miles on it.

Schlimmer sent the engine to AMSOIL INC. for analysis. Analysis showed that a valve keeper had worn out, causing the valve to become wedged in the chamber. The problem with the engine was not oil-related. Measurements taken against manufacturer’s specifications indicated the engine was still in useable condition. In each of five categories, the engine tested within 1 percent of manufacturer’s original specifications for the engine. (See chart below) Schlimmer replaced the engine and continues to drive the van with the original transmission with more than 1 million miles of service. Cylinder and piston with high mileage cam bearings with no wear no rod wear crankshaft specifications no valve stem wear

The engine valve train shown here is clean, with virtually no deposits in an area that typically has sludge and heavy carbon buildup with conventional motor oil.

The inside of the valve cover is very clean with almost no deposits.

The top of the head reveals the rockers and valve springs have almost no deposits. Note the part numbers still are visible.

Based on measurements, the engine could be put back in service.

The cylinder wall reveals no noticeable ridges. Note the crosshatch marks still are present.

The uncleaned oil pan shows no sludge or heavy varnish.

Pickup screen has 930,599 miles

The engine oil pump pickup screen is very clean and has no deposits.


The lower crankcase shows no deposits.


The upper main bearing shows very little wear. All of the main bearings from the engine are in useable condition, according to the analysis.

Where to get product
Click on this button

Order AMSOIL now using the easy application guide

Place your order immediately using the application guide. Enter your year, make and model of your vehicle. Shipping is fast and very economical.

What fits all your vehicles

Interstate Battery System of Detroit very satisfied with the results of Amsoil in their fleet!

Running a 10W30 oil for 240 hours!

AMSOIL was the first synthetic oil

Mercedes-Benz and motor oil law suits

Interceptor 2-cycle oil

Companies wanting to buy out AMSOIL

Harley-Davidson Oil. Which is better?

Regarding your factory warranty

Crackdown of obsolete oils in California

Company History

Motorcycle Fluids